So it seems that the draw() function isn't being called consistently on API 31, but is on API 32+. I'll raise on the Compose Issue Tracker.

https://issuetracker.google.com/issues/318679450

I'll have another play tomorrow and see if I can get something working. If not I'll probably have to bump up the min SDK level for the blur impl to 32 for now.

I hope I can add some context as to the origins and the reason why this bug happens. It appears that everything is okay on the Compose side. The issue here is with the RenderNode. My hypothesis is that on API 31, it fails to refresh on the JNI side if its position has not updated since the latest draw call. More specifically, in this part of the code:

private fun Effect.updateRenderNodePosition() {
    renderNode.setPosition(0, 0, bounds.width.toInt(), bounds.height.toInt())
    renderNode.translationX = bounds.left
    renderNode.translationY = bounds.top
    renderNodeDirty = false
  }

If we feed different positions at each call, the RenderNode is updated successfully. It is not acceptable to use in the library, of course, but I wrote a little dirty hack to reproduce this behavour: https://github.com/gleb-skobinsky/haze/blob/main/haze/src/androidMain/kotlin/dev/chrisbanes/haze/AndroidHazeNode.kt

The video is so short because github does not accept long screen recordings :)

UPD: I managed to remove the freeze on SDK level 31 without the hacks! Just applied the translation to the setPosition method instead of translation in the record lambda. Check out the source code

It took hours to debug this...

Great detective work @gleb-skobinsky! Send a PR over?

Yes, I will create a PR today